Device for stacking and reseparating flat rectangular items of mail, such as letters

ABSTRACT

1,067,589. Feeding and stacking sheets. TELEFUNKEN PATENTVERWERTUNGS G.m.b.H. Aug. 4, 1964 [Aug. 2, 1963], No. 30790/64. Headings B6B and B6H. In apparatus wherein letters or other flat items of mail are stacked on edge on a moving belt and moved towards separating means, and the stack is replenished continuously by feeding the letters &amp;c. between a movable pusher carriage and the end of the stack, the carriage is normally driven forward whenever the belt is driven, and is controlled by a sensing member on the carriage which senses the pressure of the carriage on the stack and responds to cause backward movement of the carriage when the pressure exceeds a predetermined value. As shown in plan in Fig. 1, a horizontal belt 1 supported on rollers 2, 3 is adapted to support a stack of letters (not shown) on edge and move it towards a separator comprising a suction belt 26 arranged on pulleys 27, 28. Guide rails 15, 16 support a carriage 17 provided with rollers 18, and letters are fed through a slot 19 in the carriage to replenish the stack on the belt 1, the stacking being facilitated by a roller 22. A motor 11 drives the roller 2 by a chain drive 9 to feed the belt 1 and a chain 14 is driven from the roller 2 at a higher speed than the belt 1 and is supported on an idler wheel 13 on the roller 3. A motor 20 on the carriage 19 has a shaft carrying a chain wheel 21 which engages the chain 14: thus, when the belt 1 is driven, the carriage 17 moves in the same direction at higher speed; but when the motor 20 is driven, the carriage 17 is moved backward due to the engagement of the wheel 21 with the chain 14. The motor 20 is controlled by a switch 25 which is operated when the pressure between the end of the letter stack and a sensing lever 24 on the carriage exceeds a predetermined value as the result of letters being fed to the stack quicker than they are being separated by the suction belt 26. When the letter stack presses against the suction belt 26 above a predetermined pressure, it causes a sensing lever 30 to operate a switch 31 to stop the motor 11. When the motor 11 and belt 1, are at rest, and letters are being fed through the slot 19 for stacking on the belt 1, the carriage 17 moves backward more or less continuously, controlled by the switch 25. In a modification (Fig. 3, not shown), the motor 20 is not mounted on the carriage, the latter is secured to the chain 14, and the two motors 11, 20 are aligned, driven in opposite directions, and coupled to a differential gearing having an output shaft arranged to drive the chain 14. When the motor 20 is switched off, the chain 14 is driven through the differential to drive the belt 1 and also the carriage 17, the latter travelling faster than the belt; but when this motor 20 is switched on by the switch 25, the drive speeds of the two motors are superimposed on one another, so that the carriage is driven at the resultant value of the two speeds, and may be driven more slowly than the belt 1, or even travel in the opposite direction. Brake motors may be used in both the above constructions. In a further modification shown in Fig. 5, the carriage 17 is attached to the chain 14 which can be driven in either direction by a reversible motor 20&lt;SP&gt;11&lt;/SP&gt; connected to a three-phase supply line, and the belt 1 is driven by a motor 11&lt;SP&gt;11&lt;/SP&gt;, both motors and switches therefor being arranged in a circuit in which relays automatically ensure the sequence of operations. The motor 11&lt;SP&gt;11&lt;/SP&gt;, which only drives the belt 1 when the separator suction belt 26 is operating, is set in motion simultaneously with the motor 20&lt;SP&gt;11&lt;/SP&gt; by operating a single manual switch, and the belt 1 and carriage 17 move in the same direction. The motor 11&lt;SP&gt;11&lt;/SP&gt; is stopped when the pressure switch 31&lt;SP&gt;11&lt;/SP&gt; is closed due to the stack pressing too heavily on the suction belt 26. The direction of rotation of the motor 20&lt;SP&gt;11&lt;/SP&gt; is reversed if the switch 25&lt;SP&gt;11&lt;/SP&gt; is closed due to the excessive pressure between the end of the stack on the sensing lever 24 on the carriage.

Jan. 16, 1968 BURKHARDT ET AL 3,363,782

DEVICE FOR STACKING AND RESEPARATING FLAT RECTANGULAR ITEMS OF MAIL,sucn AS LETTERS 4 Sheets-Sheet 1 Filed July 29, 1964 ]n ven tors Mguyd:a m

fittovn 946$ Jan. 16, 1968 G. BURKHARDT ET AL 3,363,782 FOR STACKING ANDRESEPARATING FLAT RECTANGULAR DEVICE ITEMS OF MAIL, SUCH AS LETTERS 4Sheets-Sheet 2 Filed July 29, 1964 7n venims:

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Jan. 16, 1968 5. BURKHARDT ET AL 3,363,782

- DEVICE FOR STACKING AND RESEPARATING FLAT RECTANGULAR OF MAIL, sUcH ASLETTERS ITEMS Filed July 29, 1964 4 Sheets-Sheet 5 7n vehfors; BisbzvtlBuYk KGXL RE 3,363,782 NGULAH 4 Sheets-Sheet 4 G. BURKHARDT ETAL G ANDRESEPARATING FLAT RECTA ITEMS OF MAIL, SUCH AS LETTERS Jan. 16, 1968DEVICE FOR STACKIN Filed July 29, 1964 United States Patent M T 11Claims. (Cl. 214-4) Claims This invention relates to a device for thesimultaneous stacking and re-separating of fiat rectangular items ofmail, such as letters. Devices of this kind are known which comprise afloor-forming belt which serves as a support for the stack and which ismoved towards the separator when the stacked items of mail are to beseparated, and a stacking carriage which is controlled by a sensingmember mounted on the stacking carriage and reponsive to the pilepressure.

In the stackers of this kind previously used, it was customary toprovide two contacts at the side of the stacking carriage supporting theend of the pile, for the control of the forward and backward travel ofthe stacking carriage according to the fullness of the stacker. Thesecontacts respond to the pressure which the stacking carriage exerts onthe pile. The first contact operates when the pressure of the stackingcarriage on the pile exceeds a predetermined limit during the forwardtravel and switches over the drive of the stacking carriage to theopposite direction of rotation so that the stacking carriage travelsbackwards. The backward movement continues until the second contactdetects that the pressure of the stacking carriage on the pile hasdropped below a predetermined pressure. This contact then again switchesthe drive of the stacking carriage back to the original direction ofrotation so that the carriage again travels forwards. This kind ofcontrol of the stacking carriage has the great disadvantage that,because of its inertia, the stacking carriage always travels somewhatbeyond the correct position and consequently, with a sensitiveadjustment of the contacts, is continuously moved backwards andforwards, that is to say it executes an oscillatory motion.

The object of the invention is to avoid such oscillatory movement. Thisis achieved in such a manner that the sensing member only serves tocontrol the backward travel of the stacking carriage and for thispurpose only responds when the pile pressure exceeds a predeterminedvalue, and that control and drive means are provided which cause theforward travel of the carriage when the sensing member does not respondand the floor belt is driven at the same time. One embodiment of theinvention includes a motor which serves for the drive of the stackingcarriage, and which motor can run selectively in both direction ofrotation in known manner and can move the stacking carriage eithertowards or away from the separator by means of a pulling device. Theelectrical switching means for the motor are designed in such a mannerthat it is only switched on in the direction of rotation which causes amovement of the carriage towards the separator if the drive for thefloor belt is switched on simultaneously.

In a further embodiment, a motor serves as driving means for thestacking carriage, which motor has such a direction of rotation andco-acts in such a manner with endless pulling means and the stackingcarriage that the latter only moves away from the separator when thesensing member detects that the predetermined pressure value has beenexceeded.

3,363,782 Patented Jan. 16, 1968 It is also possible, within the scopeof the invention for the drive of the floor belt to cause the drive ofthe stacking carriage towards the separator by means of endless pullingmeans running parallel with the floor belt, while the drive of thestacking carriage for the opposite direction of movement co -acts withthe endless pulling means and the stacking carriage in such a mannerthat, during the period when the mentioned first drive is switched on,the stacking carriage receives a speed component opposite to theaforesaid one and which may be greater, in its absolute value, than thefirst component.

Said pulling means may, to advantage, be constructed in the form of anendless chain.

It has further proved to be an advantage to mount the drive for thestacking carriage on the carriage itself and to cause it to co-act withthe chain by means of a sprocket mounted on its shaft in such a mannerthat when the motor on the stacking carriage is switched on, the latterreceives a speed component which is superimposed on its original one sothat movement in the opposite direction results.

Another possible embodiment of the invention is one in which a fixedlymounted differential gearing is provided, to the one input shaft thedrive of the floor belt is coupled and to the other input shaft of whichthe drive of the stacking carriage is coupled, and the differentialgearing drives through its drive shaft, a chain secured to the stackingcarriage.

These and further features of the invention will now be described withreference to the accompanying drawings:

FIGURE 1 shows in plan view a first example of an embodiment of a deviceaccording to the invention;

FIGURE 2 shows a side view of this device in section along the lineII-II of FIGURE 1;

FIGURE 3 shows in plan View a further embodiment;

FIGURE 4 shows the circuit diagram of a third embodiment of theinvention as shown in FIGURE 5.

As shown in FIGURES 1 and 2, a floor belt 1 is provided for the supportof items of mail (not illustrated here for the sake of clarity). Thisfioor belt runs over guide pulleys 2 and 3 in the direction of the arrowshown. Bearing brackets 6 and 7, which support the guide pulleys 2 and3, are securedto base plates 4 and 5. Secured to one end of the journalof the guide pulley 2 is a chain wheel 8 which is driven by a firstmotor 11 through a chain 9 and a second chain wheel 10, and sets thefloor belt 1 in motion. A chain wheel 12 is likewise secured to theother end of the journal of the guide pulley 2, but has such a pitchdiameter that a higher speed is imparted to the chain 14 than to thefloor belt 1. A further idling chain wheel 13 is mounted on the journalof the guide pulley 3 to guide the chain 14. The chain is driven by thechain wheel 12 in such a manner that it moves in the direction of thearrow. Mounted beside the floor belt 1 and parallel thereto are twoguide rails 1.5 and 16 which rest on the base plates 4 and 5 and onwhich a stacking carriage 17 can move by means of its rollers 18. Thefeed of the items of mail to be stacked is effected from the side wherethe guide rail 15 is located through a slot 19in the direction of thearrow. The conveyor belts which serve to convey and guide the items ofmail to this slot 19 and the associated conveying rollers are not shownfor the sake of clarity and because they are of no interest in thisconnection. A second motor 20 is mounted on the stacking carriage andits shaft carries a chain wheel 21 which co-acts with the chain 14. Aso-called stacking roller 22 is also mounted on the stacking carriage 17as well as a sensing lever 24 which is pivotable about a pin 23. Thissensing lever, actuates a contact, for example a microswitch 25, andresponds to pressure to switch on the motor 20 when the pressure exertedby the pile on the stacking carriage, and hence on the sensing lever 24,

3 exceeds a predetermined value, and it switches the motor off againwhen the pressure drops below a predetermined value.

Mounted at the end of the floor belt 1, at the side of the pile remotefrom the stacking carriage 17 is a separating belt 26 which is driven inthe direction of the arrow by one of the guide pulleys 27, 28 when theitems in the pile have to be separated individually. The separating belt26 is constructed in the form of a belt with groups of holes and co-actswith a suction chamber 29. Finally, between this belt and the pile thereis mounted a sensing lever 39 which co-acts with a rnicroswitch 31 todetect when the pressure of the pile towards the separating belt 26exceeds a predetermined value. The microswitch 31 then switches off thedrive of the floor belt 1, that is to say the motor 11.

The mode of operation of the embodiment of the invention described is asfollows:

It is assumed, as the normal case, that a series of items of mail havealready been piled up in the stacker and that the separator is runningcontinuously. In this case, the floor belt, too, runs continuouslybecause the sensing lever 30 does not detect too great an increase inthe pile pressure at the separator. The stacking carriage 17 is likewisedisplaced continuously towards the separator with the motor 20 stopped.If now the stacking up of new items takes place more quickly than theirseparation, the pile grows. The sensing lever 24 detects an increase inthe pressure of the pile on the stacking carriage 17 and switches on themotor 20. The latter imparts to the carriage a relative movement counterto the direction in which the floor belt is running, as a result of itschain wheel 21 running in engagement with the chain 14, so that thestacking carriage moves backwards and the pile pressure drops despitethe arrival of fresh items of mail. When this pressure drops below acertain predetermined value, the sensing lever 24 again switches off themotor 20 of the stacking carriage through the switch 25, so that thecarriage again begins to move towards the separator by being pulled bythe chain 14 driven by the floor belt motor.

If stacking only is to be effected with the separator stopped, the floorbelt 1 is also at rest. The stacking carriage moves backwards more orless continuously, controlled by the switch 25, according to the arrivalof fresh items to be stacked.

Finally, the case maybe considered in which only separation is carriedout but no stacking up of fresh items of mail takes place. In this case,the stacking carriage follows the pile under the pull of the chain, and,as a result of its higher speed in comparison with that of the floorbelt, it increases the pressure on the pile until the sensing lever 24switches on the motor 20 through the switch 25. This drives the stockingcarriage for a short time in the opposite direction so that the carriagelags behind in relation to the floor belt until the pressure of thestacking carriage on the pile has become lower.

With this mode of operation of the device according to the invention itis clear that the control of the movement of the stacking carriage canbe finely adjusted both in the two extreme cases, where the separator isstopped or the stacking up is stopped, and with every possible state ofmovement of the device between these extremes for each of these phases.

FIGURE 3 shows another embodiment of the invention. All the componentswhich were used in the device as shown in FIGURES 1 and 2 are given thereference numerals used in these figures. The difference between thedevice shown in FIGURE 3 in comparison with that already described isthat the motor 20 is no longer mounted on the movable stacking carriage,but fixedly mounted and that a differential gearing 32 is provided, andcoupled to one input shaft 33 is the first motor 11 and to the othershaft 34 is the second motor 20'. With chain wheel 35 secured thereto,the output shaft of the differential gearing drives the chain 14 whichruns over a chain wheel 36. This can no longer be mounted on the shaftof the guide pulley 3 of the floor belt but is independently mounted.The direction of rotation of the two motors 11 and 20 is such thatdifferent directions of rotation are set up at the two input shafts ofthe ditterential gearing. When the motor 20' is switched off, a speeddetermined by the motor 11' is imparted to the stacking carriage by thedifferential gearing 32, which speed is somewhat higher than that of thefioor belt because of the gear ratio. When the motor 20' is switched on,however, the drive speeds of the two motors are superimposed on oneanother so that the stacking carriage is driven by the differencebetween the two speeds including the plus or minus signso that thestacking carriage lags behind in comparison with the movement of thefloor belt or even travels in the opposite direction.

In this device, the motion of the stacking carriage depending on theconditions prevailing in the stacker coincide with that of the stackingcarriage in the device shown in FIGURES 1 and 2, but here the drive ofthe stacking carriage is not effected directly by a motor securedthereto but the speed and/or the direction of movement of the drivechain 14 of the stacking carriage is varied by the differential gearing32.

In the embodiments described with reference to FIG- URES 1 to 3, it isan advantage to construct both motors in the form of brake motors.

Apart from these two mechanical solutions, the invention can also berealised by an electric control of the two motors as shown in FIGURE 4.FIGURE 5 shows a device which is designed for this control and in whichthe mechanical construction is very similar to that of the device shownin FIGURE 3. Instead of the motor 20, which has only one direction ofrotation, in this th rd embodiment a motor 20" is used which runs inboth directions of rotation and drives the stacking carriage directlythrough a chain wheel 35 and a chain 14. In this embodiment, the motor20 and the motor 11 for the drive of the floor belt are combined intheir operation through their electrical control, but mechanically theywork entirely independently of one another.

The motor 20" is connected to the mains through the contactors SI, SII,which can switch over the phase, whereas the motor 11 is connected tothe mains through a single contactor 5111. In the energising circuit forthe relay Rsl is the switch 31" which switches on the floor belt inFIGURES l and 3, and the switch 37 which is only actuated if theseparator is to operate. The switch 25", which is actuated by thesensing lever 24 (FIGURES 1 and 3), is shown as a make contact whichenergizes the relay Rs2 when being closed, that is to say when thepressure of the pile becomes too great at the stacking carriage.

The contactors SI and S11 cause the switching on of the motor 20" andthe switching over of its direction of rotation. In the energizingcircuit of SI, there are a make contactors 211, a break contact .911,and a parallel connection of make contacts S111 and rslII. The contactor5111 causes the switching on of the motor 11".

A make contact rs2I and a break contact .91 are in the energizingcircuit of the contactor $11.

With the switches and relay contacts in the position described, thecircuit operates as follows: The switch 31" is already in the positionfloor belt running. The floor belt should only begin to run, however,when the separator is switched on. When this has been done throughactuation of the switch 37, the relay R91 is operated. Through theclosing of its contact rsll, this relay energizes the contactor SIII. Atthe same time, through the closing of its contact rslII, it energizesthe contactor SI. Thus, the floor belt motor 11 and the stackingcarriage motor 20" are switched on simultaneously and the contact s1 isopened. The stacking carriage travels towards the separator. Inaddition, the contactor SIII closes its contact sIII which is connectedin parallel with the contact rslII. This contact sIII is, however, of nosignificance with regard to the starting operation.

When the sensing lever on the stacking carriage detects that thepressure exerted by the pile on the stacking carriage is exceeding apredetermined value, it closes the switch 25". Now the relay Rs2 isenergized. It closes its contact rsZl and opens its contact rsZII. Thecontactor SI releases and the contact s1 is closed: on the other handthe contactor S11 is energized. The contactor SI is switched over and sothe direction of rotation of the stackingcarriage motor 20" is reversed.The stacking carriage then runs backwards in the manner alreadydescribed. In addition, the contactor SII opens its contact .911.

If the pressure of the pile on the sensing lever at the separatorexceeds a predetermined value during any phase of movement of thestacking carriage, for example dur ing its advance, then the switch 31"is opened and the relay Rsl releases. The latter also happens when theseparator is switched off, for example. The relay Rsl opens its twocontacts rslI and rslII. The motor of the stacking carriage is, however,not stopped at this moment but only after the contactors $111, which isno longer energized after the closing of the contact rslI has releasedand opened its contact sIII.

If, however, the stacking carriage happens to be moving backwards, whenthe relay Rs1 releases as a result of the opening of one of the switchesinserted in its energizing circuit, the movement of the stackingcarriage is not disturbed as a result. As already mentioned, theparallel connection of the contacts S111 and rslII offers a particularadvantage. By this means, the effect is achieved that thestacking-carriage motor 20" is switched on simultaneously with the floorbelt motor 11" and it is not necessary to wait for the energization ofthe contactor $111. On the other hand, when both motors are switched offthe motor 20" is switched off first since the contactor III has alsoreleased; thus the motor 20 is switched off later thanthe motor 11". Bythis means, it is possible to ensure that the stacking carriage, whichreaches its operating speed more slowly than the floor belt, always hasa lead over the floor belt even under unfavorable operating conditions,for example with very frequent switching on and off of the motor.

The auxiliary contacts s1 and sII in the energizing circuits of thecontactors SI and 811 are provided for the protection of the motor 20".It is impossible to avoid that the contacts of the contactors SI/SIIstick during a change-over operation, particularly after a large numberof switching operations. In such a case, during the next switching overof the motor 20" to the opposite direction of rotation, the secondcontactor would be actuated, although the first is still switched on.This is avoided by the provision of the two contacts s1 and sII becausethe auxiliary contact in the energizing circuit of the one contactor isalways open when the other contactor is energized. This auxiliarycontact remains open until the contacts of the energized contactor areopened again.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. A device for stacking flat articles, comprising, in combination:

(a) a floor belt providing a support for -a pile of flat articles;

(b) means for continuously driving said floor belt toward a separatingzone when articles are to be separated;

(c) a stacking carriage adjacent said floor belt and movable toward andaway from said separating zone for retaining a pile of flat articlesbetween said carriage and said separating zone;

(d) sensing means on said carriage for responding to the pressure of thepile when a predetermined pile pressure is exceeded; and

(e) control and drive means for causing the stacking carriage to movebackwardly away from said separating zone When said sensin meansresponds and for causing the stacking carriage to move forwardly onlywhen (1) the sensing means does not respond, and (2) the floor belt isbeing driven.

2. A device as defined in claim 1 wherein said driving means iselectrically controlled and said control and drive means includes abidirectional motor which can selectively run in either direction,pulling means connected to said motor and said carriage for moving thecarriage toward and away from said separating zone, and electricalswitching means for controlling said motor so that it is only switchedon in the direction of rotation which causes the carriage to move towardthe separating zone if said sensing means does not respond and if thedriving means for the floor belt is switched on at the same time.

3. A device for stacking flat articles, comprising, in combination:

(a) a floor belt providing a support: for a pile of flat articles;

(b) means for driving said floor belt toward a separating zone;

(c) a stacking carriage adjacent said floor belt and movable toward andaway from said separating zone for retaining a pile of flat articlesbetween said carriage and said zone;

(d) sensing means on said carriage for responding to the pressure of thepile; and

(e) control and drive means for causing the stacking carriage to movebackwardly away from said separating zone when activated by said sensingmeans which occurs only when a predetermined pile pressure is exceededand for causing the stacking carriage to move forwardly which occurswhen the sensing means does not respond and while the floor belt isbeing driven, said control and drive means including a motor and endlesspulling means connected to said carriage, said motor having such adirection of rotation that it coacts with the endless pulling means andthe stacking carriage so the latter only moves away from the separatingzone when the sensing means detects that the predetermined pile pressurehas been exceeded.

4. A device as defined in claim 3 wherein said driving means includesendless pulling means extending parallel to the floor belt for drivingthe stacking carriage forwardly, said control and drive means for movingthe carriage backwardly coacting with said endless pulling means and thecarriage so that during the period when the driving means is activatedthe carriage is provided with a speed component in the forward directionwhich may be greater in its absolute value than the component in thebackward direction.

5. A device as claimed in claim 4, characterised in that the endlesspulling means is a chain.

6. A device as defined in claim 5 wherein said control and drive meansincludes a motor mounted on said carriage and having a chain wheelconnected thereto and coacting with said chain so that when the motor isactivated a speed component in the backward direction is superimposed onthe original speed component acting on the carriage in the forwarddirection.

7. A device as claimed in claim 6, characterised in that the motormounted on the stacking carriage can only assume a specific and constantspeed of rotation.

8. A device as defined in claim 5 wherein fixedly mounted differentialgearing is provided having two input shafts one of which is a portion ofsaid driving means and the other of which is a portion of said controland drive means and having an output shaft driving the chain which isconnected to said carriage.

9. A device for stacking flat articles, comprising, in combination:

(a) a floor belt providing a support for a pile of fiat articles;

(b) means for driving said floor belt toward a separating zone;

(c) a stacking carriage adjacent said floor belt and movable toward andaway from said separating zone for retaining a pile of fiat articlesbetween said carriage and said zone;

((1) first sensing means on said carriage for responding to the pressureof the pile;

(e) control and drive means for causing the stacking carriage to movebackwardly away from said separating zone when activated by said sensingmeans which occurs only when a predetermined pile pressure is exceededand for causing the stacking carriage to move forwardly which occurswhen the sensing means does not respond and while the floor belt isbeing driven; and

(f) second sensing means disposed in said Zone and responding to pilepressure for stopping said driving means when the pile pressure at saidzone rises above a predetermined value.

10. A device for stacking fiat articles, comprising, in

combination:

(a) a floor belt providing a support for a pile of fiat articles;

(b) means for driving said floor belt toward a separating zone;

(c) a stacking carriage adjacent said floor belt and movable toward andaway from said separating zone for retaining a pile of flat articlesbetween said carriage and said zone;

(d) sensing means on said carriage for responding to the pressure of thepile;

(e) control and drive means for causing the stacking carriage to movebackwardly away from the separating zone when activated by said sensingmeans which occurs only when a predetermined pile pressure is exceededand for causing the stacking carriage to move forwardly which occurswhen the sensing means does not respond and while the floor belt isbeing driven, said control and drive means including a motor and endlesschain means arranged so that said endless chain means runs somewhatfaster than said floor belt.

11. A device for stacking fiat articles, comprising, in

combination:

(a) a floor belt providing a support for a pile of flat articles;

(b) means for driving said floor belt toward a separating zone;

(c) a stacking carriage adjacent said floor belt and movable toward andaway from said separating zone for retaining a pile of fiat articlesbetween said carriage and said zone;

(d) sensing means on said carriage for responding to the pressure of thepile;

(e) control and drive means for causing the stacking carriage to movebackwardly away from the separating zone when activated by said sensingmeans which occurs only when a predetermined pile pressure is exceededand for causing the stacking carriage to move forwardly which occurswhen the sensing means does not respond and while the floor belt isbeing driven, said control and drive means including brake motors.

References Cited UNITED STATES PATENTS 2,572,509 10/1951 Novick 2'7l-622,584,730 2/1952 Novick 27162 3,051,333 8/1962 Richert et al 214'73,152,701 10/1964 Weiland 214-7 GERALD M. FORLENZA, Primary Examiner.

I. E. OLDS, Assistant Examiner.

1. A DEVICE FOR STACKING FLAT ARTICLES, COMPRISING, IN COMBINATION: (A)A FLOOR BELT PROVIDING A SUPPORT FOR A PILE OF FLAT ARTICLES; (B) MEANSFOR CONTINUOUSLY DRIVING SAID FLOOR BELT TOWARD A SEPARATING ZONE WHENARTICLES ARE TO BE SEPARATED; (C) A STACKING CARRIAGE ADJACENT SAIDFLOOR BELT AND MOVABLE TOWARD AND AWAY FROM SAID SEPARATING ZONE FORRETAINING A PILE OF FLAT ARTICLES BETWEEN SAID CARRIAGE AND SAIDSEPARATING ZONE; (D) SENSING MEANS ON SAID CARRIAGE FOR RESPONDING TOTHE PRESSURE OF THE PILE WHEN A PREDETERMINED PILE PRESSURE IS EXCEEDED;AND (E) CONTROL AND DRIVE MEANS FOR CAUSING THE STACKING CARRIAGE TOMOVE BACKWARDLY AWAY FROM SAID SEPARATING ZONE WHEN SAID SENSING MEANSRESPONDS AND FOR CAUSING THE STACKING CARRIAGE TO MOVE FORWARDLY ONLYWHEN (1) THE SENSING MEANS DOES NOT RESPOND, AND (2) THE FLOOR BELT ISBEING DRIVEN.